Abstract: The present disclosure relates to compositions and methods of modulating inflammatory and immune responses through binding of SAA to TLR2 in a subject (e.g., human, non-human primate, rodent, etc.), and compositions and methods for screening TLR2 agonists and antagonists. In the studies described herein, a potential role of SAA in neutrophilia was investigated and the results demonstrated that SAA is a potent inducer for macrophage secretion of G-CSF, which leads to neutrophilia in mice. Using G-CSF?/? and TLR2?/? mice, it was found that the SAA-induced neutrophilia is dependent on TLR2-mediated production of G-CSF. Based on direct binding assay and gain-of-function studies in TLR2-transfected cells, SAA was identified as a novel ligand for TLR2 and a link between increased SAA concentration and TLR2-mediated inflammatory responses such as neutrophilia was established. Additional embodiments are disclosed.

Abstract: The present disclosure relates to compositions and methods of modulating inflammatory and immune responses through binding of SAA to TLR2 in a subject (e.g., human, non-human primate, rodent, etc.), and compositions and methods for screening TLR2 agonists and antagonists. In the studies described herein, a potential role of SAA in neutrophilia was investigated and the results demonstrated that SAA is a potent inducer for macrophage secretion of G-CSF, which leads to neutrophilia in mice. Using G-CSF?/? and TLR2?/? mice, it was found that the SAA-induced neutrophilia is dependent on TLR2-mediated production of G-CSF. Based on direct binding assay and gain-of-function studies in TLR2-transfected cells, SAA was identified as a novel ligand for TLR2 and a link between increased SAA concentration and TLR2-mediated inflammatory responses such as neutrophilia was established. Additional embodiments are disclosed.